One admin password for thousands of accounts on a website... Is there any password manager add-on that will automatically insert it for any username?

I'm a support agent and I have a task that requires logging in to 4000+ user accounts with my admin password. After entering the password manually for the 150th time I started wondering if there is a more efficient way to do this.

Is there any password manager that will automatically put the same password for -any- username on a specific website?

I'm a support agent and I have a task that requires logging in to 4000+ user accounts with my admin password. After entering the password manually for the 150th time I started wondering if there is a more efficient way to do this.
Is there any password manager that will automatically put the same password for -any- username on a specific website?

Rather than a more sophisticated form filler, perhaps you want to find a really dumb one that doesn't recognize that password fields should be different for different usernames?

Alternately, you could use a purpose-built userscript. A userscript requires either the Greasemonkey or Scriptish extension, and can be custom tailored for any site you like. Unfortunately, userscripts do not use secure storage, so this may not be acceptable with something like an admin password.

Can you paste it?
Rather than a more sophisticated form filler, perhaps you want to find a really dumb one that doesn't recognize that password fields should be different for different usernames?
Alternately, you could use a purpose-built userscript. A userscript requires either the Greasemonkey or Scriptish extension, and can be custom tailored for any site you like. Unfortunately, userscripts do not use secure storage, so this may not be acceptable with something like an admin password.

Chosen Solution

jscher2000, cor-el, thank you so much for pushing me in the right direction.

Update:
I've just found an auto-filler that has the password field: https://addons.mozilla.org/uk/firefox/addon/autofill-262804/ It was easier than I thought.
jscher2000, cor-el, thank you so much for pushing me in the right direction.